This invention relates generally to the field of collapsible shipping containers of relatively large dimensions which are suitable for use in conjunction with palletized loads, and more particularly to an improved form adapted for use in the shipping of fluid loads.
Traditional containers of this type have found wide acceptance in the field of air transport and other fields where the larger rigid type container used on ships and freight cars is not suitable. The collapsible container normally consists of a rectangular box mounted on a rigid pallet or the equivalent, to permit convenient handling by a fork lift truck. Because of the rigidity of reinforcing bottoms, depending upon the type of cargo, such containers are readily stackable when in loaded condition.
When the containers have been unloaded, the same are readily collapsed upon the pallet or equivalent, and the collapsed side walls thereof are placed in mutually parallel relation, following which a removable cover which is part of the erected container overlies the collapsed walls and forms a unit only several inches high which may also be stacked for return shipment.
Depending upon the nature of the intended cargo, the containers have been modified to include side walls having spouts and small sliding doors in addition to the removable top cover. In the case of particulate loads, it is also known to provide flexible cords interconnecting between opposed side walls to prevent bulging. Because of potential leakage problems, no attempt, to the best of my knowledge has been made to accommodate liquid loads.
It is known in the art to provide relatively small containers with an inner liquid-proof fused lining of polyethylene or the like to make them waterproof, such containers normally not being intended for reuse. It is also known to package relatively inert liquid, such as milk in polyethylene bags which are supported prior to use in a relatively rigid frame element which permits the milk to be poured from the bag, following which the bag is discarded and the frame reused. However, such expedients are not suitable for shipping relatively larger quantities of liquids which would otherwise normally be shipped in heavy steel drums, which are expensive and space-consuming when return shipment is made in empty condition.